# wait-on - wait for files, ports, sockets, http(s) resources wait-on is a cross-platform command line utility which will wait for files, ports, sockets, and http(s) resources to become available (or not available using reverse mode). Functionality is also available via a Node.js API. Cross-platform - runs everywhere Node.js runs (linux, unix, mac OS X, windows) wait-on will wait for period of time for a file to stop growing before triggering availability which is good for monitoring files that are being built. Likewise wait-on will wait for period of time for other resources to remain available before triggering success. For http(s) resources wait-on will check that the requests are returning 2XX (success) to HEAD or GET requests (after following any redirects). wait-on can also be used in reverse mode which waits for resources to NOT be available. This is useful in waiting for services to shutdown before continuing. (Thanks @skarbovskiy for adding this feature) [![Build Status](https://travis-ci.com/jeffbski/wait-on.svg?branch=master)](https://travis-ci.com/jeffbski/wait-on) ## Installation Latest wait-on version 7+ requires Node.js 12+ wait-on versions 4-6 requires Node.js 10+ (Node.js v8 users can use wait-on@5.3.0, v4 users can still use wait-on@2.1.2, and older Node.js engines, use wait-on@1.5.4) ```bash npm install wait-on # local version OR npm install -g wait-on # global version ``` ## Usage Use from command line or using Node.js programmatic API. ### CLI Usage Assuming NEXT_CMD is the command to run when resources are available, then wait-on will wait and then exit with a successful exit code (0) once all resources are available, causing NEXT_CMD to be run. wait-on can also be used in reverse mode, which waits for resources to NOT be available. This is useful in waiting for services to shutdown before continuing. (Thanks @skarbovskiy for adding) If wait-on is interrupted before all resources are available, it will exit with a non-zero exit code and thus NEXT_CMD will not be run. ```bash wait-on file1 && NEXT_CMD # wait for file1, then exec NEXT_CMD wait-on f1 f2 && NEXT_CMD # wait for both f1 and f2, the exec NEXT_CMD wait-on http://localhost:8000/foo && NEXT_CMD # wait for http 2XX HEAD wait-on https://myserver/foo && NEXT_CMD # wait for https 2XX HEAD wait-on http-get://localhost:8000/foo && NEXT_CMD # wait for http 2XX GET wait-on https-get://myserver/foo && NEXT_CMD # wait for https 2XX GET wait-on tcp:4000 && NEXT_CMD # wait for service to listen on a TCP port wait-on socket:/path/mysock # wait for service to listen on domain socket wait-on http://unix:/var/SOCKPATH:/a/foo # wait for http HEAD on domain socket wait-on http-get://unix:/var/SOCKPATH:/a/foo # wait for http GET on domain socket ``` ``` Usage: wait-on {OPTIONS} resource [...resource] Description: wait-on is a command line utility which will wait for files, ports, sockets, and http(s) resources to become available (or not available using reverse flag). Exits with success code (0) when all resources are ready. Non-zero exit code if interrupted or timed out. Options may also be specified in a config file (js or json). For example --config configFile.js would result in configFile.js being required and the resulting object will be merged with any command line options before wait-on is called. See exampleConfig.js In shell combine with && to conditionally run another command once resources are available. ex: wait-on f1 && NEXT_CMD resources types are defined by their prefix, if no prefix is present, the resource is assumed to be of type 'file'. Resources can also be provided in the config file. resource prefixes are: file: - regular file (also default type). ex: file:/path/to/file http: - HTTP HEAD returns 2XX response. ex: http://m.com:90/foo https: - HTTPS HEAD returns 2XX response. ex: https://my/bar http-get: - HTTP GET returns 2XX response. ex: http://m.com:90/foo https-get: - HTTPS GET returns 2XX response. ex: https://my/bar tcp: - TCP port is listening. ex: 1.2.3.4:9000 or foo.com:700 socket: - Domain Socket is listening. ex: socket:/path/to/sock For http over socket, use http://unix:SOCK_PATH:URL_PATH like http://unix:/path/to/sock:/foo/bar or http-get://unix:/path/to/sock:/foo/bar Standard Options: -c, --config js or json config file, useful for http(s) options and resources -d, --delay Initial delay before checking for resources in ms, default 0 --httpTimeout Maximum time in ms to wait for an HTTP HEAD/GET request, default 0 which results in using the OS default -i, --interval Interval to poll resources in ms, default 250ms -l, --log Log resources begin waited on and when complete or errored -r, --reverse Reverse operation, wait for resources to NOT be available -s, --simultaneous Simultaneous / Concurrent connections to a resource, default Infinity Setting this to 1 would delay new requests until previous one has completed. Used to limit the number of connections attempted to a resource at a time. -t, --timeout Maximum time in ms to wait before exiting with failure (1) code, default Infinity Use postfix 'ms', 's', 'm' or 'h' to change the unit. --tcpTimeout Maximum time in ms for tcp connect, default 300ms Use postfix 'ms', 's', 'm' or 'h' to change the unit. --httpTimeout Maximum time to wait for the HTTP request, default Infinity Use postfix 'ms', 's', 'm' or 'h' to change the unit. -v, --verbose Enable debug output to stdout -w, --window Stability window, the time in ms defining the window of time that resource needs to have not changed (file size or availability) before signalling success, default 750ms. If less than interval, it will be reset to the value of interval. This is only used for files, other resources are considered available on first detection. -h, --help Show this message ``` ### Node.js API usage ```javascript var waitOn = require('wait-on'); var opts = { resources: [ 'file1', 'http://foo.com:8000/bar', 'https://my.com/cat', 'http-get://foo.com:8000/bar', 'https-get://my.com/cat', 'tcp:foo.com:8000', 'socket:/my/sock', 'http://unix:/my/sock:/my/url', 'http-get://unix:/my/sock:/my/url' ], delay: 1000, // initial delay in ms, default 0 interval: 100, // poll interval in ms, default 250ms simultaneous: 1, // limit to 1 connection per resource at a time timeout: 30000, // timeout in ms, default Infinity tcpTimeout: 1000, // tcp timeout in ms, default 300ms window: 1000, // stabilization time in ms, default 750ms // http options ca: [ /* strings or binaries */ ], cert: [ /* strings or binaries */ ], key: [ /* strings or binaries */ ], passphrase: 'yourpassphrase', proxy: false /* OR proxy config as defined in axios. If not set axios detects proxy from env vars http_proxy and https_proxy https://github.com/axios/axios#config-defaults { host: '127.0.0.1', port: 9000, auth: { username: 'mikeymike', password: 'rapunz3l' } } */, auth: { user: 'theuser', // or username pass: 'thepassword' // or password }, strictSSL: false, followRedirect: true, headers: { 'x-custom': 'headers' }, validateStatus: function (status) { return status >= 200 && status < 300; // default if not provided } }; // Usage with callback function waitOn(opts, function (err) { if (err) { return handleError(err); } // once here, all resources are available }); // Usage with promises waitOn(opts) .then(function () { // once here, all resources are available }) .catch(function (err) { handleError(err); }); // Usage with async await try { await waitOn(opts); // once here, all resources are available } catch (err) { handleError(err); } ``` waitOn(opts, [cb]) - function which triggers resource checks - opts.resources - array of string resources to wait for. prefix determines the type of resource with the default type of `file:` - opts.delay - optional initial delay in ms, default 0 - opts.interval - optional poll resource interval in ms, default 250ms - opts.log - optional flag which outputs to stdout, remaining resources waited on and when complete or errored - opts.resources - optional array of string resources to wait for if none are specified via command line - opts.reverse - optional flag to reverse operation so checks are for resources being NOT available, default false - opts.simultaneous - optional count to limit concurrent connections per resource at a time, setting to 1 waits for previous connection to succeed, fail, or timeout before sending another, default infinity - opts.timeout - optional timeout in ms, default Infinity. Aborts with error. - opts.tcpTimeout - optional tcp timeout in ms, default 300ms - opts.verbose - optional flag which outputs debug output, default false - opts.window - optional stabilization time in ms, default 750ms. Waits this amount of time for file sizes to stabilize or other resource availability to remain unchanged. - http(s) specific options, see https://nodejs.org/api/tls.html#tls_tls_connect_options_callback for specific details - opts.ca: [ /* strings or binaries */ ], - opts.cert: [ /* strings or binaries */ ], - opts.key: [ /* strings or binaries */ ], - opts.passphrase: 'yourpassphrase', - opts.proxy: undefined, false, or object as defined in axios. Default is undefined. If not set axios detects proxy from env vars http_proxy and https_proxy. https://github.com/axios/axios#config-defaults ```js // example proxy object { host: '127.0.0.1', port: 9000, auth: { username: 'mikeymike', password: 'rapunz3l' } } ``` - opts.auth: { user, pass } - opts.strictSSL: false, - opts.followRedirect: false, // defaults to true - opts.headers: { 'x-custom': 'headers' }, - cb(err) - if err is provided then, resource checks did not succeed ## Goals - simple command line utility and Node.js API for waiting for resources - wait for files to stabilize - wait for http(s) resources to return 2XX in response to HEAD request - wait for http(s) resources to return 2XX in response to GET request - wait for services to be listening on tcp ports - wait for services to be listening on unix domain sockets - configurable initial delay, poll interval, stabilization window, timeout - command line utility returns success code (0) when resources are availble - command line utility that can also wait for resources to not be available using reverse flag. This is useful for waiting for services to shutdown before continuing. - cross platform - runs anywhere Node.js runs (linux, unix, mac OS X, windows) ## Why I frequently need to wait on build tasks to complete or services to be available before starting next command, so this project makes that easier and is portable to everywhere Node.js runs. ## Get involved If you have input or ideas or would like to get involved, you may: - contact me via twitter @jeffbski - - open an issue on github to begin a discussion - - fork the repo and send a pull request (ideally with tests) - ## License - [MIT license](http://github.com/jeffbski/wait-on/raw/master/LICENSE)